The present invention is generally related to healthcare monitoring systems. More particularly, the present invention is directed to the detection of infectious diseases in individuals or communities.
Bioterrorism is the use of biological agents to intentionally produce disease in unsuspecting and susceptible individuals or populations. Bioterrorism has become an increasing concern throughout the world, and particularly in the United States. While still requiring a high level of expertise and financial resources, advances in biotechnology have made the production and dissemination of pathogenic organisms or chemical toxins a real threat. Because of this significant threat, it is of paramount importance for the government, public health community, and the medical profession to be prepared for this type of health emergency.
Early detection of a bioterrorism attack is crucial. Some biological agents cause diseases that have relatively short incubation periods, and have high mortality rates when proper treatment is not initiated early in the course of infection. For biological agents that can be transmitted from person-to-person, it is even more crucial to identify the disease early. The Centers for Disease Control and Prevention (CDC) has listed as Category A (high-priority agents include organisms that pose a risk to national security) many potential agents including Bacillus anthracis (anthrax), variola major virus (smallpox), Yersinia pestis (pneumonic plague), filovirus (Ebola hemorrhagic fever), filovirus (Marburg hemorrhagic fever), Lassa—arena virus (Lassa fever), Junin—arena virus (Argentine hemorrhagic fever) and Francisella tularensis (tularemia). Identification of these agents is difficult because they are not expected, and most healthcare providers are not familiar with them. All of the above present symptoms that include fevers.
Human anthrax has three major clinical forms: cutaneous, gastrointestinal, and inhalation. Cutaneous anthrax is a result of introduction of a spore through the skin. Gastrointestinal anthrax is a result of the introduction of a spore by ingestion. Inhalation anthrax is a result of introduction of a spore through the respiratory tract. After an incubation period, inhalation anthrax presents as fever, malaise, fatigue, cough, mild chest discomfort and possibly vomiting and abdominal pain. This stage can last for hours or days. In untreated patients, there may or may not be a period of improvement. The patient then abruptly develops severe respiratory distress with dyspnea, diaphoresis, stridor, and cyanosis. Shock and death occur within 24-36 hours after the onset of severe symptoms. Case fatality rates for inhalation anthrax are thought to approach 90-100%.
From Oct. 4 to Nov. 2, 2001, the first ten confirmed cases of inhalation anthrax caused by intentional release of Bacillus anthracis (“B. anthracis”) were identified in the United States. Epidemiological investigation indicated that the outbreak, in the District of Columbia, Florida, New Jersey, and New York, resulted from intentional delivery of B. anthracis spores through mailed letters or packages. The median age of patients was 56 years, 70% were male. The median incubation from the time of exposure to onset of symptoms, when known, was four days. Symptoms at initial presentation included fever or chills, sweats, fatigue or malaise, minimal or non-productive cough, dyspnea, and nausea or vomiting. The median white blood cell count was 9.8×103/mm3.
Smallpox was declared eradicated by the World Health Organization in 1980. Two repositories were approved to hold the remaining variola major virus. These two reference laboratories are the CDC in Atlanta, Ga., and a laboratory in Moscow. During the past several years, accusations have been made that the smallpox virus was weaponized in the Soviet Union, and there is concern that virus stores may have been moved to additional sites. Routine vaccination for smallpox in the United States was discontinued among civilians in 1972. The immune status of individuals vaccinated before that time is not certain, but immunity is believed to decline substantially within ten years of vaccination. Therefore, there is a high susceptibility to this infection world-wide. Smallpox transmission is person-to-person by respiratory discharges, by direct contact with skin lesions, or contact with contaminated bedding or clothing. The incubation period averages 12-14 days, with the range being 7-17 days. Individuals are not infectious until the onset of a rash. Smallpox infection begins with an abrupt onset of fever, malaise, rigors, vomiting, headache, and backache. Lesions appear 2-3 days later. Mortality is approximately 30%; death is thought to occur from toxemia associated with circulating immune complexes and soluble variola major antigens.
If a bioterrorism event, such as the release of a Class A biological warfare agent upon a populated area, can be detected before infected persons experience initial symptoms, which include low-grade fevers (defined as 100 to 102 degrees Fahrenheit), 90 percent of the infected individuals can be saved. Yet, the only existing detection systems in place in the U.S. rely on activity reports from emergency medical services, hospitals, clinics, physicians, epidemiologists and coroners. In other words, there is no detection system in place that alerts health officials before individuals experience initial symptoms.
Various electronic detectors for a variety of biological warfare agents have been and are being developed. The obvious questions with these are where to place them and how many will be needed to be effective? Biological warfare agents are targeted to kill people wherever they gather, such as in homes, schools, malls, stadiums, factories, offices, churches, gymnasiums, public buildings, retail stores, postal facilities, government buildings, hospitals, restaurants, entertainment facilities and city streets. People gather in small and large groups, and at different times and at different places. Electronic detectors cannot possibly be positioned everywhere people might gather.